Obesity, type 2 diabetes, and coronary artery disease (blockages in arteries that circulate blood) are all caused by impaired metabolism. They are created when residue from food is deposited in the circulation rather than being fully converted into and used as energy to propel us forward. The best way to prevent these health issues is to turbocharge our metabolism.

Odds are you’ve heard about intermittent fasting. Simply defined as “periodic abstinence from eating,” it is something that humans have been doing throughout history, originally out of necessity and later as part of just about every religious or cultural tradition. Because of the way humans have evolved, our physiology is best suited to cycle between feast and famine and is not well suited for a prolonged feasting phase (fed state). Lately, the potential medical benefits of intermittent fasting have increasingly been substantiated in animal and medical research projects and now extend to improved longevity, weight loss, metabolism (i.e., energy delivery to the cells), cancer treatment, and brain power.

Based on my clinical experience, I often have my patients experiment with the idea of shrinking their eating window to roughly eight hours a day. This means restricting “feeding times” to eight hours within the twenty-four-hour day, leaving the remaining sixteen hours to digest and metabolize the food. This allows time for the body to optimally extract and distribute the energy from the food. For example, the “feeding time” could open at 9 a.m. (yes, coffee or tea counts), and close at 5 p.m., allowing the remaining hours for the body to be in an unfed state. In the unfed state, the insulin level can drop, allowing stored fat to be depleted as the body burns it for energy. Feeding and the subsequent process of energy extraction and delivery are stressors on the system and require a period of time (the unfed state) before the next feeding cycle begins.

The best time to open the feeding window is soon after waking up, as insulin sensitivity is highest in the morning and diminishes as the day progresses. This means the body is most receptive to an energy bolus (a dose of energy) earlier in the day and burns energy more efficiently during that period. Thus, eating a significant chunk of the day’s food before noon has distinct advantages. Some people find it easy to skip breakfast and prefer to start the feeding window at 11 a.m. or even noon — and that works okay too — but remember, the first sip of coffee or tea starts the timer!

The efficacy of intermittent fasting hinges on two key factors: one is the duration of the feeding window (eight hours), and the other is the timing. As Ruth Patterson, professor of family medicine and public health at the University of California, San Diego, points out: “There has been so much energy on what we eat and on carbohydrates, and it’s only very recently that there have been studies to say that we have been ignoring timing, and timing might be as important.”

Tweaking meal timing and frequency may be the low-hanging fruit in our quest for health, wellness, and longevity. While we may debate about the adage “You are what you eat,” there is no doubt that when you eat can really make a huge difference.

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Pankaj Vij, MD, FACP, is the author of Turbo Metabolism. As a doctor of internal medicine, he has helped thousands of patients lose weight, manage chronic health conditions, and improve their physical fitness. Visit him online at www.doctorvij.com.